When it comes to optimizing query performance in SQL Server, it’s important to consider more than just the query execution plan. One often overlooked aspect is the amount of data being retrieved from the server to the client side. This can have a significant impact on query performance, regardless of the query cost.
So, how can we determine the amount of data being retrieved? While visually inspecting the result set can provide some insights, it’s not always practical, especially when dealing with large datasets. Fortunately, SQL Server Management Studio provides a feature called Client Statistics that can help us measure the amount of data retrieved from the server to the client side.
Enabling Client Statistics is simple and can be done in three different ways:
- Press SHIFT+ALT+S together.
- Go to Menu >> Query >> Include Client Statistics.
- Once enabled, a new tab will appear in the result span when clicked.
Client Statistics captures details for different trials and compares them with each other. The results are displayed using green and red arrows to indicate improved and degrading statistics, respectively. It’s important to note that an increase in statistics doesn’t always imply a good result. Sometimes, an increase can actually indicate a negative impact on performance.
The display window shows an average of the latest 10 trials. When the 11th trial is added, the very first trial is dropped, ensuring that the average is always based on the most recent data.
Client Statistics is a powerful tool that can help identify performance bottlenecks related to data retrieval. By monitoring the amount of data being transferred from the server to the client side, you can make informed decisions to optimize your queries and improve overall performance.
Do you use Client Statistics in SQL Server? If so, what do you use it for? Share your experiences and insights in the comments below!